How To Karambit on a sharpmaker

[Bo-dacious]

Hey guys, I just got a sharp maker and I'm trying to sharpen a karambit on it. I get it a little bit sharper but it mostly tears Pape when I try to cut it.

I do 40 strokes on the corner of the brown rods then 40 strokes on the corners of the white rods. I keep the knife perfectly upright just like all the times I was successful with regular knives.

(I tried a regular knife for the first time and I accidentally didn't lay the knife on the flat surface. It just touched the corner. It didn't get sharp. So how can the corners alone make a karambit sharp?)

Please give me your thoughts guys.

Thanks,

Bo

 

[Bo-dacious]

Should I do soft strokes or hard strokes? Should I use the corner that makes the most sound or the least sound when I do a stroke? Should I go fast or slow? Any other variations I should know about?

Bo

 

[Dfunk1210]

Are you pulling your edge straight through on each stroke? Since Karambits are curved blades, you need to rotate along the edge on each stroke, like you would do on any belly or recurve. maybe this is your problem. what kind of steel is it.

EDIT: also you should just let the weight of the knife do the work. Don't force it

 

[bucketstove]

Goodness gracious , great Bo-Dacious

Look at your left hand?
Look at your right hand?
What is in your hands?
There are only three choices: knife, abrasive, marker.
You're using sharpmaker, so your real choices are : knife , marker, ruler.
Two markers do nothing for you, just like two knives.
You need a knife and marker.
Do you have marker?
Where is your marker?
What did you marker tell you about your blade angles?
What does a ruler tell you about your edge bevel widths?


- a little bit sharper but it mostly tears paper
In other words apex has not been reached, more strokes needed.

How many more? Is a coarser abrasive needed?
Unknown, use marker and a ruler to get some idea.
One side probably needs more work than the other, the marker will tell you what is what.

To shorten the amount of strokes needed increase angle.

- I do 40 strokes on the corner of the brown rods then 40 strokes on the corners of the white rods.

The spyderco sharpmaker simple set of instructions is for beginners,
and you Bo-dacious have moved past that.

If 40 strokes on medium stone doesn't work, the 40 strokes on fine dont do anything.
You only switch from coarser stone to finer stone, after the coarser stone has done its work, after you have apexed, after you can slice paper.

Yes, marker can also be used for this, but its mostly useful for seeing where you're grinding.


Fine stones are very fine, switching too early simply slows you down.


Counting helps you keep both sides even.
Counting can tell you if you're sharpening or regrinding/changing/lowering angles.
Marker trick tells you this 300 strokes quicker.

- I keep the knife perfectly upright just like all the times I was successful with regular knives.

That is an approach that can work to get you sharp,
if your sharpening angle is high enough to reach the edge
or better yet the apex (quicker)

Marker trick will tell you exactly where you're grinding.
Red and esp Green marker are easier to see than black marker.


If 15dps or 20dps, the built-in sharpmaker setting, aren't hitting the apex, you can increase the angle by shimming

But remember, if you're not following the curve of the edge and keeping the edge perpendicular to the stone, the angle will change. If angle is not reaching apex, this changing will take time.



- can the corners alone make a karambit sharp?
Of course, the corners are abrasive just like the rest of the sharpmaker stones.
But the surface area is smaller so the pressure is higher.
You could take advantage of this for faster material removal behind the apex,
but its usually better to stick to the flats,
and use lower grits for faster material removal.

- Should I do soft strokes or hard strokes?

Using the flats.
Keep it about 0.5lb to 1lb or more for working the edge bevels. Keep it under 1/2 lb, as close to 1oz for working on the apex, microbevel/deburring.


In general, for ex with diamonds/soft waterstones, do not use more force than required to remove metal.
This is less on corners than on the flats.
The very apex is very small and easily rolled/chipped, and light force is required.


- Should I use the corner that makes the most sound or the least sound when I do a stroke?
Stick to the flats ?
Each stone sounds different so learn to go by feel and not by sound.
Use a scale to help you learn to feel.

If you're using the flats,
1-3lb for shaping, working the edge bevels, 1mm or wider. Under 1/2lb as close to 20 grams or under 1oz as you can get for apex/deburr/microbevel.
Without a scale pay attention to bevel width and the stone "grab".
If you're not using enough force the blade will skate on the stone,
as you increase force you'll feel the stone grab the blade,
this is like the minimal force you use for sharpening,
higher for wider bevels,
smaller for narrower bevels,
for apex/microbevel/deburr its very very very small like 20 grams or under 1oz
as you keep increasing force you'll feel more grab, until the feeling levels out -- thats your maximum force you want to use if the stone can handle it.

shaping force, think like brushing your teeth ... about 0.5lb to 1lb for diamonds
apexing force, think like touching the pointy tip of a pencil or nail or pushpin with your fingertip. You control power with your arm not your fingertips...


but first learn what the marker and ruler have to tell you.


- Should I go fast or slow?
Go as fast as you can and maintain control.
2-4 scrubbing up/down strokes per second should be comfortable
with not a lot of practice.
Faster than that is possible but tiring.


- Any other variations I should know about?
First get to know the basic variation know it like the back of your hand

 

[Obsessed with Edges]

Should I do soft strokes or hard strokes? Should I use the corner that makes the most sound or the least sound when I do a stroke? Should I go fast or slow? Any other variations I should know about?

Bo

Faster pace - NO
Louder 'sound' in grinding - NO
Harder pressure - NO

All of these approaches above are things that'll increase pressure laterally against the apex, and will create many more problems than they solve, like heavy burring on softer steels or chipping on rather hard steels. It'll also make the rods load up & clog much, much sooner, which exacerbates the same issues (burring, etc). If you're hearing a lot of grinding noise or really feeling the grinding via your hands (are your hands getting tired or sore?), then it's way too much pressure. I'm betting the karambit is relatively soft steel, so burring is more likely and the burrs will be more challenging to clean up with anything but patient, very light passes against the hones; BIG, HEAVY burrs will take a very long time to remove at that rate.

To detect when you've apexed, you do want to have some light burring to let you know you're there; but, too much pressure will create a heavy, thick burr that 'folds' too soon, while it's much too thick, and then it'll be a pain to remove it.

And don't count strokes. It's not really as helpful as simply watching progress via the Sharpie method and watching for a burr to form. Observing the symmetry of the edge, from side-to-side, will tell you if you're spending too much time on one side or the other. Don't move from your coarsest rod until you've confirmed the presence of a full-length burr along the edge, and flipped it to the other side at least once. Then lighten pressure some more, and use that same rod to very gently hone the thickness of the burr down, to remove as much as possible and/or thin it enough that it'll come off easily in the remaining steps.

 

[Bo-dacious]

Dfunk: it's stainless steel, What does that tell you?

Bucketstove: what exactly is shimming?
You mean use the flats on a karambit? I thought it wouldn't work because it's a rounded edge.
What kind of scale do you mean for learning the feel? Like a weigh scale that tells me how much weight I'm using?
What is microbebeveling?

Thanks a lot for the help guys,

Bo

 

[Dfunk1210]

Dfunk: it's stainless steel, What does that tell you?

Bucketstove: what exactly is shimming?
You mean use the flats on a karambit? I thought it wouldn't work because it's a rounded edge.
What kind of scale do you mean for learning the feel? Like a weigh scale that tells me how much weight I'm using?
What is microbebeveling?

Thanks a lot for the help guys,

Bo

I only ask because not all steels are equal. Some simply take more work than others. The guys above know what they are talking about. But either way, maybe its your technique. look at vids of people putting curved blades to a sharpmaker. maybe that will help.

 

[Bo-dacious]

Also, if I find with a marker that the angle on the edge is too steep and the sharp maker can't accommodate it, what should I do? Does the steel Conform to the rod or am I screwed?

Bo

 

[Bo-dacious]

Thanks Dfunk,

Bo

 

[Bo-dacious]

OK I tried again with the marker and I discovered that I wasn't removing material from the apex, as I suspected. I tried angling The knife a bit and it removed marker from the apex but it didn't get that much sharper. Just a bit sharper. Is there protocol for this scenario? What should I do?

 

[bgentry]

I think you are missing the geometry here. A Karambit is a full hawkbill, so it's entire blade is a recurve. A curved blade that is curved inward, which is the opposite of most curved blades, which curve outward.

So, the ENTIRE blade is a recurve, which means you have to use a curved blade stroke through the entire blade edge. This is unlike regular blades where part of the stroke is straight and the other part is a "curved stroke".

You should start with the heel of the blade contacting the CORNER of a sharpmaker stone. The handle should be roughly parallel to the table at this point. You will draw the knife backwards towards you. At the same time, you will be moving the handle downwards. At the end of the stroke, the tip of the blade should be touching the stone. The handle will probably be nearly vertical at this point.

The idea is to maintain a 90 degree "normal line" between the blade edge and the stone. This is probably very confusing without diagrams or videos. This video shows how to follow an outward curve, perfectly, on any blade. Use the principles in this video to follow your inward curve. Everything is exactly the same. Face the normal line of the blade 90 degrees to the stone at all times. Which means moving the handle downwards as you pull back.

What is probably happening with your blade is, you are not following the geometry. So, instead of the blade edge touching the stone, you are only hitting further up on the blade. This is common and normal with a curved blade if you do not follow the curve. It's one reason why so many people just can't get the curved section of a blade sharp. This is exacerbated by the shape of a recurve, which a karambit is.

Good luck to you!

Brian.

 

[bucketstove]

Bucketstove: what exactly is shimming?
You mean use the flats on a karambit? I thought it wouldn't work because it's a rounded edge.
What kind of scale do you mean for learning the feel? Like a weigh scale that tells me how much weight I'm using?
What is microbebeveling?

Shimming is wedging. Or
Shimming is that dance you do when you put the sugar/salt packet underneath a chair leg so the chair doesnt wobble.
Its how you can increase or lower angle of a sharpmaker past the built in settings.
You can use post it notes under a corner.
Or place a Spyderco Rod under the middle of the Sharpmaker, you get to change degrees of the rods by 3* dregrees: 12 17 18 23


The marker will tell you if the flats work or don't work right quick. Hint, of course they work.
The corners are pretty much for serrations, the flats are for everything else.
Its very easy to overpressure on a corner, the flats give you more wiggle room, more abrasive.

Seeing how a scale was mentioned alongside pounds/oz/grams, yes, a scale that measures pounds/oz/grams would be the kind to use to tell you how many pounds/oz/grams youre using so you can know what 1lb feels like what 1oz feels like...

Microbeveling , well that is simply making microbevels. Say you raise a burr at 15dps, you cut it off with a few passes at 20dps. Thats a microbevel. Its micron sized like the apex. Apex is around 1 micron. Printer paper is around 100 micron thick. A "micro" bevel should be under 100 microns.

Also, if I find with a marker that the angle on the edge is too steep and the sharp maker can't accommodate it, what should I do? Does the steel Conform to the rod or am I screwed?

Pick an option already described (regrind or increase angle)
Steel that "conforms" is weak/damaged steel.

OK I tried again with the marker and I discovered that I wasn't removing material from the apex, as I suspected. I tried angling The knife a bit and it removed marker from the apex but it didn't get that much sharper. Just a bit sharper. Is there protocol for this scenario? What should I do?

Hi,
Are you joking?
Sounds like you've got a defective knife/equipment
you must throw it all away immediately,
do not refund,
do not resell,
do not giveaway,
do not try and fix it,
directly into the garbage it must all go after being smashes with a hammer.
Yes hammer the equipment into itty bitty pieces is step number one .

knife not sharp but marker being removed? do more strokes.

 

[bucketstove]

So, the ENTIRE blade is a recurve, which means you have to use a curved blade stroke through the entire blade edge. This is unlike regular blades where part of the stroke is straight and the other part is a "curved stroke".

The idea is to maintain a 90 degree

I've got a better idea maybe.
if you start with tip you pivot the same way as a regular sharpening
here it is compared to spydercosharpmaker.pdf instruction





update: regular blade for comparison to hawkbill, you start at the top of the stone and you pivot down for any curve as you move down the stone

 

[Bo-dacious]

Hey guys. I wrote a whole big thing but it deleted. Thank you for all your help, I figured it out. I got a mildly curved karambit sharp (I assume and hope I can get more curved ones sharp) I wasn't having trouble with keeping the edge perpendicular, the problem was the apex not getting touched by the stone. I sharpened a lower angle karambit and it worked. I'm going to buy the cubic Boron nitrate rods to change the angle of steep knives.
I'm very happy I got this to work and I have you guys to thank!

Cheers guys,

Bo

 

[JD Spydo]

One other thing that you might find helpful when using your Spyderco 204 Sharpmaker. I've been using my Sharpmaker well over 17 years now and I've sharpened about every blade style and geometry imaginable. One thing I tell everyone who gets a 204 Sharpmaker and you may think my advice is for elementary school age kids but trust me it does help as simple as it is. First and foremost take and watch the instructional video that Spyderco provides at least 2 to 3 times before even attempting to sharpen anything. Second try you luck at sharpening a couple of el-cheapo kitchen knives or maybe a really old, antiquated folder you may have had for years. Do all of that before trying to sharpen a premium, high dollar blade>> it won't take long you'll see the sense in my advice.

Now one last thing to keep in mind with Spyderco's ceramic stones. I've found that if I clean the stones frequently it helps a lot. I rarely sharpen more than two blades before getting out the Bar Keeper's Friend cleanser to clean it with. The cleaner those stones are the more uniform and consistent the bite/abrasion is. Those simple tips will have you sharpening all your blades as sharp as a straight razor after a little practice. Do keep us posted as to how you're doing >> the Sharpmaker is an excellent sharpening tool once you learn the tricks to using it.